 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.registry;

 import java.util.ArrayList ;
 import java.util.Collection ;
 import java.util.HashMap ;
 import java.util.Iterator ;
 import java.util.List ;

 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtension;
 import org.eclipse.core.runtime.IExtensionPoint;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.dynamichelpers.ExtensionTracker;
 import org.eclipse.core.runtime.dynamichelpers.IExtensionChangeHandler;
 import org.eclipse.core.runtime.dynamichelpers.IExtensionTracker;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.dialogs.IWorkingSetPage;

 /**
  * Stores working set descriptors for working set extensions.
  */
 public class WorkingSetRegistry implements IExtensionChangeHandler {
     // used in Workbench plugin.xml for default workingSet extension
 // @issue this is an IDE specific working set page!
 private static final String DEFAULT_PAGE_ID = "org.eclipse.ui.resourceWorkingSetPage"; //$NON-NLS-1$

     private HashMap /*<String, WorkingSetDescriptor>*/ workingSetDescriptors = new HashMap ();

     /**
      *
      */
     public WorkingSetRegistry() {
         IExtensionTracker tracker = PlatformUI.getWorkbench()
                 .getExtensionTracker();
         tracker.registerHandler(this, ExtensionTracker
                 .createExtensionPointFilter(getExtensionPointFilter()));

     }

     /**
      *
      * @return
      * @since 3.3
      */
     private IExtensionPoint getExtensionPointFilter() {
         return Platform.getExtensionRegistry().getExtensionPoint(
                 PlatformUI.PLUGIN_ID,
                 IWorkbenchRegistryConstants.PL_WORKINGSETS);
     }
     
     /**
      * Adds a working set descriptor.
      *
      * @param descriptor working set descriptor to add. Must not
      * exist in the registry yet.
      */
     public void addWorkingSetDescriptor(WorkingSetDescriptor descriptor) {
         Assert.isTrue(!workingSetDescriptors.containsValue(descriptor),
                 "working set descriptor already registered"); //$NON-NLS-1$
 IExtensionTracker tracker = PlatformUI.getWorkbench()
                 .getExtensionTracker();
         tracker.registerObject(descriptor.getConfigurationElement()
                 .getDeclaringExtension(), descriptor,
                 IExtensionTracker.REF_WEAK);
         workingSetDescriptors.put(descriptor.getId(), descriptor);
     }

     /**
      * Returns the default, resource based, working set page
      *
      * @return the default working set page.
      */
     public IWorkingSetPage getDefaultWorkingSetPage() {
         // @issue this will return the IDE resource working set page... not good for generic workbench
 WorkingSetDescriptor descriptor = (WorkingSetDescriptor) workingSetDescriptors
                 .get(DEFAULT_PAGE_ID);

         if (descriptor != null) {
             return descriptor.createWorkingSetPage();
         }
         return null;
     }

     /**
      * Returns the working set descriptor with the given id.
      *
      * @param pageId working set page id
      * @return the working set descriptor with the given id.
      */
     public WorkingSetDescriptor getWorkingSetDescriptor(String pageId) {
         return (WorkingSetDescriptor) workingSetDescriptors.get(pageId);
     }

     /**
      * Returns an array of all working set descriptors.
      *
      * @return an array of all working set descriptors.
      */
     public WorkingSetDescriptor[] getWorkingSetDescriptors() {
         return (WorkingSetDescriptor[]) workingSetDescriptors.values().toArray(
                 new WorkingSetDescriptor[workingSetDescriptors.size()]);
     }
     
     /**
      * Returns an array of all working set descriptors having
      * a page class attribute
      *
      * @return an array of all working set descriptors having a
      * page class attribute
      */
     public WorkingSetDescriptor[] getNewPageWorkingSetDescriptors() {
         Collection descriptors= workingSetDescriptors.values();
         List result= new ArrayList (descriptors.size());
         for (Iterator iter= descriptors.iterator(); iter.hasNext();) {
             WorkingSetDescriptor descriptor= (WorkingSetDescriptor)iter.next();
             if (descriptor.getPageClassName() != null) {
                 result.add(descriptor);
             }
         }
         return (WorkingSetDescriptor[])result.toArray(new WorkingSetDescriptor[result.size()]);
     }
     
     /**
      * Returns <code>true</code> if there is a working set descriptor with
      * a page class attribute. Otherwise <code>false</code> is returned.
      *
      * @return whether a descriptor with a page class attribute exists
      */
     public boolean hasNewPageWorkingSetDescriptor() {
         Collection descriptors= workingSetDescriptors.values();
         for (Iterator iter= descriptors.iterator(); iter.hasNext();) {
             WorkingSetDescriptor descriptor= (WorkingSetDescriptor)iter.next();
             if (descriptor.getPageClassName() != null) {
                 return true;
             }
         }
         return false;
     }
     
     public WorkingSetDescriptor[] getUpdaterDescriptorsForNamespace(
             String namespace) {
         Collection descriptors = workingSetDescriptors.values();
         List result = new ArrayList ();
         for (Iterator iter = descriptors.iterator(); iter.hasNext();) {
             WorkingSetDescriptor descriptor = (WorkingSetDescriptor) iter
                     .next();
             if (namespace.equals(descriptor.getUpdaterNamespace())) {
                 result.add(descriptor);
             }
         }
         return (WorkingSetDescriptor[]) result
                 .toArray(new WorkingSetDescriptor[result.size()]);
     }
     
     public WorkingSetDescriptor[] getElementAdapterDescriptorsForNamespace(
             String namespace) {
         Collection descriptors = workingSetDescriptors.values();
         List result = new ArrayList ();
         for (Iterator iter = descriptors.iterator(); iter.hasNext();) {
             WorkingSetDescriptor descriptor = (WorkingSetDescriptor) iter
                     .next();
             if (namespace.equals(descriptor.getDeclaringNamespace())) {
                 result.add(descriptor);
             }
         }
         return (WorkingSetDescriptor[]) result
                 .toArray(new WorkingSetDescriptor[result.size()]);
     }

     /**
      * Returns the working set page with the given id.
      *
      * @param pageId working set page id
      * @return the working set page with the given id.
      */
     public IWorkingSetPage getWorkingSetPage(String pageId) {
         WorkingSetDescriptor descriptor = (WorkingSetDescriptor) workingSetDescriptors
                 .get(pageId);

         if (descriptor == null) {
             return null;
         }
         return descriptor.createWorkingSetPage();
     }

     /**
      * Loads the working set registry.
      */
     public void load() {
         WorkingSetRegistryReader reader = new WorkingSetRegistryReader();
         reader.readWorkingSets(Platform.getExtensionRegistry(), this);
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.runtime.dynamichelpers.IExtensionChangeHandler#addExtension(org.eclipse.core.runtime.dynamichelpers.IExtensionTracker, org.eclipse.core.runtime.IExtension)
      */
     public void addExtension(IExtensionTracker tracker, IExtension extension) {
         WorkingSetRegistryReader reader = new WorkingSetRegistryReader(this);
         IConfigurationElement[] elements = extension.getConfigurationElements();
         for (int i = 0; i < elements.length; i++) {
             reader.readElement(elements[i]);
         }
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.runtime.dynamichelpers.IExtensionChangeHandler#removeExtension(org.eclipse.core.runtime.IExtension, java.lang.Object[])
      */
     public void removeExtension(IExtension extension, Object [] objects) {
         for (int i = 0; i < objects.length; i++) {
             if (objects[i] instanceof WorkingSetDescriptor) {
                 WorkingSetDescriptor desc = (WorkingSetDescriptor) objects[i];
                 workingSetDescriptors.remove(desc.getId());
             }
         }
     }
 }

